Photodynamic antimicrobial chemotherapy activities of porphyrin- and phthalocyanine-platinum nanoparticle conjugates
- Authors: Managa, Muthumuni Elizabeth
- Date: 2015
- Subjects: Photochemotherapy , Anti-infective agents , Porphyrins , Phthalocyanines , Platinum , Nanoparticles , Bioconjugates , Electrospinning
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4539 , http://hdl.handle.net/10962/d1017919
- Description: This work reports on the conjugation of differently shaped Pt nanoparticles (PtNPs) with ClGa(III) 5,10,15,20-tetrakis-(4-carboxyphenyl) porphyrin (1) as well as chloro - (5,10,15,20-tetrakis (4- (4- carboxy phenycarbonoimidoyl) phenyl) porphyrinato) gallium(III) (2) The work also reports on platination of dihydroxosilicon octacarboxyphthalocyanine (OH)₂SiOCPc (3) to give dihydroxosilicontris(diaquaplatinum)octacarboxyphthalocyanine (OH)₂SiOCPc(Pt)₃ (4). The resulting conjugates were used for photodynamic antimicrobial chemotherapy against S. aureus, E. coli and C. albicans. The degree of photo-inactivation is dependent on concentration of the conjugates, light dose (fluence) and illumination time. The log reduction obtained for 1 when conjugated to cubic PtNPs was 4.64 log (which indicate 99.99 percent of the bacteria have been killed), which is much higher than 3.94 log unit for 1-hexagonal PtNPs and 3.31 log units for 1-unshaped PtNPs. Complex 2 conjugated to hexagonal PtNPs showed 18 nm red shift in the Soret band when compared to 2 alone. Complex 2 and 2-hexagonal PtNPs as well showed promising photodynamic antimicrobial chemotherapy (PACT) activity against S. aureus, E. coli and C. albicans in solution where the log reduction obtained was 4.92, 3.76, and 3.95 respectively for 2-hexagonal PtNPs. The singlet oxygen quantum yields obtained were higher at 0.56 for 2-hexagonl PtNPs in DMF while that of 2 was 0.52 in the same solvent. This resulted in improved PACT activity for 2-hexagonal PtNPs compared to 2. Complex 4 showed slight blue shifting of the absorption spectrum when compared to complex 3 The antimicrobial activity of 4 were promising as the highest log reduction value was observed when compared to the porphyrin conjugates.
- Full Text:
- Date Issued: 2015
- Authors: Managa, Muthumuni Elizabeth
- Date: 2015
- Subjects: Photochemotherapy , Anti-infective agents , Porphyrins , Phthalocyanines , Platinum , Nanoparticles , Bioconjugates , Electrospinning
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4539 , http://hdl.handle.net/10962/d1017919
- Description: This work reports on the conjugation of differently shaped Pt nanoparticles (PtNPs) with ClGa(III) 5,10,15,20-tetrakis-(4-carboxyphenyl) porphyrin (1) as well as chloro - (5,10,15,20-tetrakis (4- (4- carboxy phenycarbonoimidoyl) phenyl) porphyrinato) gallium(III) (2) The work also reports on platination of dihydroxosilicon octacarboxyphthalocyanine (OH)₂SiOCPc (3) to give dihydroxosilicontris(diaquaplatinum)octacarboxyphthalocyanine (OH)₂SiOCPc(Pt)₃ (4). The resulting conjugates were used for photodynamic antimicrobial chemotherapy against S. aureus, E. coli and C. albicans. The degree of photo-inactivation is dependent on concentration of the conjugates, light dose (fluence) and illumination time. The log reduction obtained for 1 when conjugated to cubic PtNPs was 4.64 log (which indicate 99.99 percent of the bacteria have been killed), which is much higher than 3.94 log unit for 1-hexagonal PtNPs and 3.31 log units for 1-unshaped PtNPs. Complex 2 conjugated to hexagonal PtNPs showed 18 nm red shift in the Soret band when compared to 2 alone. Complex 2 and 2-hexagonal PtNPs as well showed promising photodynamic antimicrobial chemotherapy (PACT) activity against S. aureus, E. coli and C. albicans in solution where the log reduction obtained was 4.92, 3.76, and 3.95 respectively for 2-hexagonal PtNPs. The singlet oxygen quantum yields obtained were higher at 0.56 for 2-hexagonl PtNPs in DMF while that of 2 was 0.52 in the same solvent. This resulted in improved PACT activity for 2-hexagonal PtNPs compared to 2. Complex 4 showed slight blue shifting of the absorption spectrum when compared to complex 3 The antimicrobial activity of 4 were promising as the highest log reduction value was observed when compared to the porphyrin conjugates.
- Full Text:
- Date Issued: 2015
Photocatalysis of 4-chloro and 4-nonylphenols using novel symmetric phthalocyanines and asymmetric porphyrin supported on polyacrylonitrite nanofibres
- Authors: Jones, Benjamin Martin
- Date: 2020
- Subjects: Nanoparticles , Phthalocyanines , Electrospinning , Porphyrins , Nanofibers , Photocatalysis , Photocatalysis -- Environmental aspects
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164770 , vital:41163
- Description: This work explores the synthesis and characterisation of novel symmetrical phthalocyanines and novel asymmetric porphyrins that have been embedded or linked respectively,and electrospun into fibres for application in the photocatalysis of environmental pollutants. The phthalocyanines contain pyrrole moieties without hetero atom linkers to maintain a rigid structure. The porphyrin contains a carboxy moiety utilized to construct an amide bond between the complex and the polymer prior to the spinning process. The new compounds were characterized by elemental analyses, proton nuclear magnetic resonance (HNMR)Fourier-transform infrared spectroscopy (FTIR), MALDI-TOF and UV-vis spectroscopy. The general trends of fluorescence, triplet and singlet oxygen quantum yields are described as well as their appropriate lifetimes. The photocatalytic activity of phthalocyanine embedded fibres were compared against those that had been dyed. Unfortunately, during the degradation process, the dyed fibres leeched compound and the studies could not be continued. It was seen that the porphyrin fibres linked to the polymer showed the most efficient photocatalytic activity against 4-cholorphenol and 4-nonylphenol due to irradiation at lower wavelengths consequently having higher frequencies and transferring more energy.
- Full Text:
- Date Issued: 2020
- Authors: Jones, Benjamin Martin
- Date: 2020
- Subjects: Nanoparticles , Phthalocyanines , Electrospinning , Porphyrins , Nanofibers , Photocatalysis , Photocatalysis -- Environmental aspects
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164770 , vital:41163
- Description: This work explores the synthesis and characterisation of novel symmetrical phthalocyanines and novel asymmetric porphyrins that have been embedded or linked respectively,and electrospun into fibres for application in the photocatalysis of environmental pollutants. The phthalocyanines contain pyrrole moieties without hetero atom linkers to maintain a rigid structure. The porphyrin contains a carboxy moiety utilized to construct an amide bond between the complex and the polymer prior to the spinning process. The new compounds were characterized by elemental analyses, proton nuclear magnetic resonance (HNMR)Fourier-transform infrared spectroscopy (FTIR), MALDI-TOF and UV-vis spectroscopy. The general trends of fluorescence, triplet and singlet oxygen quantum yields are described as well as their appropriate lifetimes. The photocatalytic activity of phthalocyanine embedded fibres were compared against those that had been dyed. Unfortunately, during the degradation process, the dyed fibres leeched compound and the studies could not be continued. It was seen that the porphyrin fibres linked to the polymer showed the most efficient photocatalytic activity against 4-cholorphenol and 4-nonylphenol due to irradiation at lower wavelengths consequently having higher frequencies and transferring more energy.
- Full Text:
- Date Issued: 2020
The synthesis and characterisation of Sn(IV) porphyrin derivatives and their potential application in anti-cancer and antimicrobial photodynamic therapy
- Authors: Dingiswayo, Somila
- Date: 2021-10
- Subjects: Porphyrins , Photochemotherapy , Cancer Photochemotherapy , Active oxygen Physiological effect , Aromaticity (Chemistry) , Tetrapyrroles , Magnetic circular dichroism , Corroles , Chlorins , Photodynamic antimicrobial chemotherapy (PACT)
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188843 , vital:44791
- Description: In photodynamic therapy (PDT), the activation of light-sensitive drugs in tumour cells produces reactive singlet oxygen species, which cause tumour destruction through a cascade of biochemical reactions. Over the years, the wavelength of activation has been shown to be a critical factor in the penetration of light. Hence the properties of photosensitiser dyes in this context shape their ability to treat deep-seated tumours. In this study, the synthesis, structural characterisation and photophysicochemical properties of a series of Sn(IV) porphyrins with meso-methylthiophenyl rings that have been prepared to study their PDT and photodynamic antimicrobial chemotherapy (PACT) activity properties are reported. The series of Sn(IV) complexes is comprised of a porphyrin (1-Sn), a corrole (2-Sn), a chlorin (3-Sn) and an N-confused porphyrin (4-Sn). Herein, the low symmetry Sn(IV) porphyrin derivatives are shown to have excellent singlet oxygen generation capabilities, and lifetimes of the triplet excited states were in the microsecond range. For example, 4-Sn had a singlet oxygen quantum yield (ФΔ) and an excited triplet state lifetime (τT) of 0.88 and 27 μs, respectively. The complexes were studied using UV-visible and magnetic circular dichroism (MCD) spectroscopies. Interestingly, the positive-to-negative sign sequences of the Faraday B0 terms of 2-Sn and 3-Sn reveal that the structural modifications involved break the degeneracy of the MOs derived from the 1eg* LUMO of the porphyrin 1-Sn. In contrast, a conventional negative-to-positive sign sequence is observed for 4-Sn, since the confusion of a pyrrole moiety also results in a large separation of the 1a1u and 1a2u MOs of the porphyrin 1-Sn that are derived from the HOMO of a C16H162−parent hydrocarbon perimeter. The trends in the electronic structures of the Sn(IV) complexes were further investigated through a series of time-dependent density functional theory calculations, so that the suitability of the different types of complex for use in singlet oxygen applications could be further explored. During in vitro photodynamic antimicrobial chemotherapy (PACT) studies, chlorin derivative 3-Sn had the highest activity towards S. aureus and E. coli with log10 reductions of 10.5 and 8.74, respectively. The unusually high activity of 3-Sn against E.coli suggests that the interaction of neutral photosensitisers with gram-negativebacteria is more complex than previously understood. Anti-cancer PDT studies demonstrated that the photosensitisers had negligible dark cytotoxicity. Upon photoirradiation, the Sn(IV) complexes consistently exhibited IC50 values lower than 15 μM against MCF-7 adenocarcinoma cells. An IC50 value of 1.4 μM for 4-Sn after activation at the deep-red region of the spectrum demonstrates that complexes of this type merit further in-depth investigation. The results provide evidence that the low-symmetry Sn(IV) chlorins and N-confused porphyrins merit further in-depth study for use in singlet oxygen applications. , Thesis (MSc) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Dingiswayo, Somila
- Date: 2021-10
- Subjects: Porphyrins , Photochemotherapy , Cancer Photochemotherapy , Active oxygen Physiological effect , Aromaticity (Chemistry) , Tetrapyrroles , Magnetic circular dichroism , Corroles , Chlorins , Photodynamic antimicrobial chemotherapy (PACT)
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188843 , vital:44791
- Description: In photodynamic therapy (PDT), the activation of light-sensitive drugs in tumour cells produces reactive singlet oxygen species, which cause tumour destruction through a cascade of biochemical reactions. Over the years, the wavelength of activation has been shown to be a critical factor in the penetration of light. Hence the properties of photosensitiser dyes in this context shape their ability to treat deep-seated tumours. In this study, the synthesis, structural characterisation and photophysicochemical properties of a series of Sn(IV) porphyrins with meso-methylthiophenyl rings that have been prepared to study their PDT and photodynamic antimicrobial chemotherapy (PACT) activity properties are reported. The series of Sn(IV) complexes is comprised of a porphyrin (1-Sn), a corrole (2-Sn), a chlorin (3-Sn) and an N-confused porphyrin (4-Sn). Herein, the low symmetry Sn(IV) porphyrin derivatives are shown to have excellent singlet oxygen generation capabilities, and lifetimes of the triplet excited states were in the microsecond range. For example, 4-Sn had a singlet oxygen quantum yield (ФΔ) and an excited triplet state lifetime (τT) of 0.88 and 27 μs, respectively. The complexes were studied using UV-visible and magnetic circular dichroism (MCD) spectroscopies. Interestingly, the positive-to-negative sign sequences of the Faraday B0 terms of 2-Sn and 3-Sn reveal that the structural modifications involved break the degeneracy of the MOs derived from the 1eg* LUMO of the porphyrin 1-Sn. In contrast, a conventional negative-to-positive sign sequence is observed for 4-Sn, since the confusion of a pyrrole moiety also results in a large separation of the 1a1u and 1a2u MOs of the porphyrin 1-Sn that are derived from the HOMO of a C16H162−parent hydrocarbon perimeter. The trends in the electronic structures of the Sn(IV) complexes were further investigated through a series of time-dependent density functional theory calculations, so that the suitability of the different types of complex for use in singlet oxygen applications could be further explored. During in vitro photodynamic antimicrobial chemotherapy (PACT) studies, chlorin derivative 3-Sn had the highest activity towards S. aureus and E. coli with log10 reductions of 10.5 and 8.74, respectively. The unusually high activity of 3-Sn against E.coli suggests that the interaction of neutral photosensitisers with gram-negativebacteria is more complex than previously understood. Anti-cancer PDT studies demonstrated that the photosensitisers had negligible dark cytotoxicity. Upon photoirradiation, the Sn(IV) complexes consistently exhibited IC50 values lower than 15 μM against MCF-7 adenocarcinoma cells. An IC50 value of 1.4 μM for 4-Sn after activation at the deep-red region of the spectrum demonstrates that complexes of this type merit further in-depth investigation. The results provide evidence that the low-symmetry Sn(IV) chlorins and N-confused porphyrins merit further in-depth study for use in singlet oxygen applications. , Thesis (MSc) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10
Photodynamic antimicrobial chemotherapy against Staphylococcus aureus and Escherichia coli sensitized using indium (III) cationic porphyrins linked to core-shell magnetic nanoparticles
- Authors: Makola, Lekgowa Collen
- Date: 2021-04
- Subjects: Photochemotherapy , Photosensitizing compounds , Staphylococcus aureus , Escherichia coli , Indium , Porphyrins , Magnetic nanoparticles , Quaternize
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/177225 , vital:42801
- Description: Photodynamic antimicrobial chemotherapy (PACT) is a well-known antimicrobial therapy technique used against multi-drug resistant pathogens. In this study, the syntheses, characterization, photophysicochemical properties, and the applications of symmetrically and asymmetrically substituted cationic indium (III) porphyrins linked to silver/copper ferrite core-shell (Ag/CuFe2O4) magnetic nanoparticles (MNPs) as potential photosensitizers for PACT are reported. The synthesized complexes include axially modified porphyrins quaternized through an axial ligand. All the asymmetrically substituted porphyrins were linked to the NPs via an ester bond and the symmetrically substituted porphyrins were linked (peripherally and /or axially) via self-assembly (Ag-S and/or Ag-N). The impact of axial modification, peripheral substituents, conjugation to the NPs, the number of positive charges, and the chain length of the alkyl halides quaternizing agents on PACT efficacy and photophysicochemical properties of porphyrins were studied. High singlet oxygen quantum yields and antimicrobial log reductions were observed. Lipophilicity and hydrophilicity of the porphyrins were also studies, where the complexes quaternized with methyl iodide showed relatively high hydrophilicity character. Upon in vitro PACT studies, the quaternized complexes were observed to have 0% viable colony, signifying their effectiveness. Moreover, the highest log reductions of 9.27 were observed against S. aureus and 9.58 were observed against E. coli. The findings from this work delineate that singlet oxygen generation alone is not a distinct factor on the PACT efficacy of the porphyrin complexes, since some of the complexes have practically the same singlet oxygen quantum but different PACT activity. However, other contributing factors including water solubility play a significant role. , Thesis (MSc) -- Faculty of Science, Department of Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Makola, Lekgowa Collen
- Date: 2021-04
- Subjects: Photochemotherapy , Photosensitizing compounds , Staphylococcus aureus , Escherichia coli , Indium , Porphyrins , Magnetic nanoparticles , Quaternize
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/177225 , vital:42801
- Description: Photodynamic antimicrobial chemotherapy (PACT) is a well-known antimicrobial therapy technique used against multi-drug resistant pathogens. In this study, the syntheses, characterization, photophysicochemical properties, and the applications of symmetrically and asymmetrically substituted cationic indium (III) porphyrins linked to silver/copper ferrite core-shell (Ag/CuFe2O4) magnetic nanoparticles (MNPs) as potential photosensitizers for PACT are reported. The synthesized complexes include axially modified porphyrins quaternized through an axial ligand. All the asymmetrically substituted porphyrins were linked to the NPs via an ester bond and the symmetrically substituted porphyrins were linked (peripherally and /or axially) via self-assembly (Ag-S and/or Ag-N). The impact of axial modification, peripheral substituents, conjugation to the NPs, the number of positive charges, and the chain length of the alkyl halides quaternizing agents on PACT efficacy and photophysicochemical properties of porphyrins were studied. High singlet oxygen quantum yields and antimicrobial log reductions were observed. Lipophilicity and hydrophilicity of the porphyrins were also studies, where the complexes quaternized with methyl iodide showed relatively high hydrophilicity character. Upon in vitro PACT studies, the quaternized complexes were observed to have 0% viable colony, signifying their effectiveness. Moreover, the highest log reductions of 9.27 were observed against S. aureus and 9.58 were observed against E. coli. The findings from this work delineate that singlet oxygen generation alone is not a distinct factor on the PACT efficacy of the porphyrin complexes, since some of the complexes have practically the same singlet oxygen quantum but different PACT activity. However, other contributing factors including water solubility play a significant role. , Thesis (MSc) -- Faculty of Science, Department of Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
Evaluation of metallophthalocyanine functionalized photocatalytic asymmetric polymer membranes for pollution control and antimicrobial activity
- Mafukidze, Donovan Musizvinoda Chidyamurimi
- Authors: Mafukidze, Donovan Musizvinoda Chidyamurimi
- Date: 2021
- Subjects: Photosensitizing compounds , Water -- Purification -- Photocatalysis , Phthalocyanines , Polymeric membranes , Porphyrins
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/171357 , vital:42052 , 10.21504/10962/171357
- Description: The conceptualisation of photosensitizing water treatment polymer membranes using phthalocyanine based photosensitizers is reported in this thesis. The key to successful preparation of stable photoactive polymer membranes was established as the covalent anchorage of the photosensitizer to a polymer, which was proven by singlet oxygen generation by the membranes without photosensitizer deterioration. Despite this limitation, the covalent linkage-incapable unsubstituted zinc (II) phthalocyanine (complex 2) was applied as a nanoconjugate of graphene quantum dots (2π(GQDs)). 2π(GQDs) was formed through π-π stacking, and was then covalently anchored, as a proof of concept. This concept was also applied to 2-(4-carboxyphenoxy) phthalocyaninato zinc (II) (complex 3) which is capable of covalent linkage but proved to deteriorate the efficiency of singlet oxygen formation with comparison to the covalent conjugates. Singlet oxygen generation by functionalized polymer membranes rendered them photocatalytic in the degradation of organic pollutants and microorganisms in water. Organic pollutant degradation capability was exemplified by 2π(GQDs) and a porphyrin-phthalocyanine heterodyad (complex 10) functionalized membranes (2π(GQDs)-memb and 10-memb respectively), where a MPc loading of approximately 0.139 μmol MPc/g of membrane was able to achieve a 4-chlorophenol degradation rate of 3.77 × 10−6 mol L−1 min−1 in a second order reaction with an initial 4-chlorophenol concentration of 3.24 × 10−4 mol L−1 for 2π(GQDs)-memb as an example. Antibacterial studies against S.aureus using a quaternized MPc and conjugates of silver triangular nanoprisms with zinc (II) and indium (III) MPcs showed note-worthy improvements in photodynamic antimicrobial chemotherapy (PACT) activity in comparison to the unquaternized MPc precursor, and the free zinc and indium MPcs respectively. Functionalization of polymer membranes with these higher activity photosensitizers translated to the formation of potentially superior biological fouling resistant membranes. The use of porphyrin-phthalocyanine polynuclei arrays (complex 10) in polymer membrane functionalization resulted in the use of a wider wavelength range (white light). The findings from this work as a whole, thus presents the potential applicability of phthalocyanine functionalized polymer membranes in water treatment technology.
- Full Text:
- Date Issued: 2021
- Authors: Mafukidze, Donovan Musizvinoda Chidyamurimi
- Date: 2021
- Subjects: Photosensitizing compounds , Water -- Purification -- Photocatalysis , Phthalocyanines , Polymeric membranes , Porphyrins
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/171357 , vital:42052 , 10.21504/10962/171357
- Description: The conceptualisation of photosensitizing water treatment polymer membranes using phthalocyanine based photosensitizers is reported in this thesis. The key to successful preparation of stable photoactive polymer membranes was established as the covalent anchorage of the photosensitizer to a polymer, which was proven by singlet oxygen generation by the membranes without photosensitizer deterioration. Despite this limitation, the covalent linkage-incapable unsubstituted zinc (II) phthalocyanine (complex 2) was applied as a nanoconjugate of graphene quantum dots (2π(GQDs)). 2π(GQDs) was formed through π-π stacking, and was then covalently anchored, as a proof of concept. This concept was also applied to 2-(4-carboxyphenoxy) phthalocyaninato zinc (II) (complex 3) which is capable of covalent linkage but proved to deteriorate the efficiency of singlet oxygen formation with comparison to the covalent conjugates. Singlet oxygen generation by functionalized polymer membranes rendered them photocatalytic in the degradation of organic pollutants and microorganisms in water. Organic pollutant degradation capability was exemplified by 2π(GQDs) and a porphyrin-phthalocyanine heterodyad (complex 10) functionalized membranes (2π(GQDs)-memb and 10-memb respectively), where a MPc loading of approximately 0.139 μmol MPc/g of membrane was able to achieve a 4-chlorophenol degradation rate of 3.77 × 10−6 mol L−1 min−1 in a second order reaction with an initial 4-chlorophenol concentration of 3.24 × 10−4 mol L−1 for 2π(GQDs)-memb as an example. Antibacterial studies against S.aureus using a quaternized MPc and conjugates of silver triangular nanoprisms with zinc (II) and indium (III) MPcs showed note-worthy improvements in photodynamic antimicrobial chemotherapy (PACT) activity in comparison to the unquaternized MPc precursor, and the free zinc and indium MPcs respectively. Functionalization of polymer membranes with these higher activity photosensitizers translated to the formation of potentially superior biological fouling resistant membranes. The use of porphyrin-phthalocyanine polynuclei arrays (complex 10) in polymer membrane functionalization resulted in the use of a wider wavelength range (white light). The findings from this work as a whole, thus presents the potential applicability of phthalocyanine functionalized polymer membranes in water treatment technology.
- Full Text:
- Date Issued: 2021
In vitro susceptibility of Staphylococcus aureus to porphyrin-silver mediated photodynamic antimicrobial chemotherapy
- Authors: Shabangu, Samuel Malewa
- Date: 2020
- Subjects: Porphyrins , Nanoparticles , Photochemotherapy , Drug resistance in microorganisms , Staphylococcus aureus
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167476 , vital:41484
- Description: This work reports on the syntheses and characterization of symmetrical and unsymmetrical porphyrin complexes namely, 5,10,15,20-tetra(4-pyridyl)-porphyrinato zinc(II) (1), 5,10,15,20-tetrathienyl porphyrinato zinc(II) (2), 5-(4-hydroxyphenyl)-10, 15, 20-tris(2-thienyl) porphyrinato zinc(II) (3), 5-(4-carboxyphenyl)-10,15,20-tris(pentafluorophenyl)- porphyrinato zinc(II) (4), 5-(4-carboxyphenyl)-10,15,20-triphenyl-porphyrinato zinc(II) (5) and 5-(4-carboxyphenyl)-10, 15, 20-tris(2-thienyl)-porphyrinato zinc(II) (6). The synthesis of silver nanoparticles (AgNPs) was also undertaken in this research work. Complexes 1, 2, 3 and 6 were linked to oleic acid/oleylamine functionalized nanoparticles via self-assembly and 4-6 were linked via covalent interaction through an amide bond to glutathione capped AgNPs. The effect of nature of bond along with symmetry were investigated, of interest were the five membered thienyl substituents. The photophysical and photochemical behaviour of the complexes and their conjugates with AgNPs were investigated in dimethylformamide. The porphyrin and AgNPs conjugates afforded an increase in singlet oxygen quantum yield. Complexes 1-6 and their conjugates were used for photodynamic antimicrobial chemotherapy of Staphylococcus aureus. The antimicrobial studies were done in two different concentrations of 0.36 and 2.0 μg/mL. The thienyl substituted porphyrin complexes and their conjugates gave better photodynamic activity as compared to phenyl analogues
- Full Text:
- Date Issued: 2020
- Authors: Shabangu, Samuel Malewa
- Date: 2020
- Subjects: Porphyrins , Nanoparticles , Photochemotherapy , Drug resistance in microorganisms , Staphylococcus aureus
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167476 , vital:41484
- Description: This work reports on the syntheses and characterization of symmetrical and unsymmetrical porphyrin complexes namely, 5,10,15,20-tetra(4-pyridyl)-porphyrinato zinc(II) (1), 5,10,15,20-tetrathienyl porphyrinato zinc(II) (2), 5-(4-hydroxyphenyl)-10, 15, 20-tris(2-thienyl) porphyrinato zinc(II) (3), 5-(4-carboxyphenyl)-10,15,20-tris(pentafluorophenyl)- porphyrinato zinc(II) (4), 5-(4-carboxyphenyl)-10,15,20-triphenyl-porphyrinato zinc(II) (5) and 5-(4-carboxyphenyl)-10, 15, 20-tris(2-thienyl)-porphyrinato zinc(II) (6). The synthesis of silver nanoparticles (AgNPs) was also undertaken in this research work. Complexes 1, 2, 3 and 6 were linked to oleic acid/oleylamine functionalized nanoparticles via self-assembly and 4-6 were linked via covalent interaction through an amide bond to glutathione capped AgNPs. The effect of nature of bond along with symmetry were investigated, of interest were the five membered thienyl substituents. The photophysical and photochemical behaviour of the complexes and their conjugates with AgNPs were investigated in dimethylformamide. The porphyrin and AgNPs conjugates afforded an increase in singlet oxygen quantum yield. Complexes 1-6 and their conjugates were used for photodynamic antimicrobial chemotherapy of Staphylococcus aureus. The antimicrobial studies were done in two different concentrations of 0.36 and 2.0 μg/mL. The thienyl substituted porphyrin complexes and their conjugates gave better photodynamic activity as compared to phenyl analogues
- Full Text:
- Date Issued: 2020
BODIPY and porphyrin dyes for direct glucose sensing and optical limiting applications
- Authors: Ndebele, Nobuhle
- Date: 2019
- Subjects: Boron compounds , Boric acid , Porphyrins , Dyes and dying -- Chemistry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/97221 , vital:31412
- Description: A series of BODIPY dyes functionalised with boronic acid in the 3,5-positions were successfully synthesised and characterised by using various analytical techniques. The dyes were prepared through a slight modification of the conventional acid catalysed condensation method. Phenylboronic acid moieties were added as styryl groups at the 3,5-positions of the 1,3,5,7-tetrametylBODIPY cores using a modified Knoevengal condensation method. The addition of the styryls resulted in the main absorption band of the dyes red-shifting to the 630−650 nm region. The photophysical and electrochemical properties of these dyes were studied to determine whether the dyes are suitable for use in the fluorescent, colourimetric and electrochemical detection of glucose. Boronic acid moieties were added as bioreceptor recognition elements because they have an affinity for carbohydrates and therefore would be able to bind and “detect” glucose. The series of BODIPY dyes did not show a “turn-on” fluorescence effect upon addition with glucose at the physiological pH. This was attributed on the basis of molecular modelling to the absence of an MO localised on the boronic-acid-substituted styryl moieties that lie close in energy to the HOMO and LUMO that facilitates the formation of an intramolecular charge transfer state. However, colourimetric changes that are visible to the naked eye are observed at basic pH when glucose was added to the dye solutions. The dyes exhibited favourable electrochemical behaviour and were able to detect glucose directly in this context when glassy carbon electrodes are modified through the drop dry method. A series of Sn(IV) porphyrins with thienyl and phenyl groups at the meso-positions were successfully synthesised and characterised. Pyridine and tetrabutyl axial ligands were added to the porphyrins to limit aggregation. The optical limiting properties of these porphyrins and three styrylated BODIPY dyes were studied in benzene and dichloromethane. Dyes were also embedded in polystyrene and studied as thin films to further gauge their suitability for use in optical limiting applications. Second-order hyperpolarizability, third-order susceptibly, non-linear absorption with reversible saturable absorption and the optical limiting threshold, were the parameters studied. Three of the four porphyrins and the three styrylated BODIPY dyes showed favourable optical limiting behaviour, which was further enhanced when the dyes are embedded in polymer thin films.
- Full Text:
- Date Issued: 2019
- Authors: Ndebele, Nobuhle
- Date: 2019
- Subjects: Boron compounds , Boric acid , Porphyrins , Dyes and dying -- Chemistry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/97221 , vital:31412
- Description: A series of BODIPY dyes functionalised with boronic acid in the 3,5-positions were successfully synthesised and characterised by using various analytical techniques. The dyes were prepared through a slight modification of the conventional acid catalysed condensation method. Phenylboronic acid moieties were added as styryl groups at the 3,5-positions of the 1,3,5,7-tetrametylBODIPY cores using a modified Knoevengal condensation method. The addition of the styryls resulted in the main absorption band of the dyes red-shifting to the 630−650 nm region. The photophysical and electrochemical properties of these dyes were studied to determine whether the dyes are suitable for use in the fluorescent, colourimetric and electrochemical detection of glucose. Boronic acid moieties were added as bioreceptor recognition elements because they have an affinity for carbohydrates and therefore would be able to bind and “detect” glucose. The series of BODIPY dyes did not show a “turn-on” fluorescence effect upon addition with glucose at the physiological pH. This was attributed on the basis of molecular modelling to the absence of an MO localised on the boronic-acid-substituted styryl moieties that lie close in energy to the HOMO and LUMO that facilitates the formation of an intramolecular charge transfer state. However, colourimetric changes that are visible to the naked eye are observed at basic pH when glucose was added to the dye solutions. The dyes exhibited favourable electrochemical behaviour and were able to detect glucose directly in this context when glassy carbon electrodes are modified through the drop dry method. A series of Sn(IV) porphyrins with thienyl and phenyl groups at the meso-positions were successfully synthesised and characterised. Pyridine and tetrabutyl axial ligands were added to the porphyrins to limit aggregation. The optical limiting properties of these porphyrins and three styrylated BODIPY dyes were studied in benzene and dichloromethane. Dyes were also embedded in polystyrene and studied as thin films to further gauge their suitability for use in optical limiting applications. Second-order hyperpolarizability, third-order susceptibly, non-linear absorption with reversible saturable absorption and the optical limiting threshold, were the parameters studied. Three of the four porphyrins and the three styrylated BODIPY dyes showed favourable optical limiting behaviour, which was further enhanced when the dyes are embedded in polymer thin films.
- Full Text:
- Date Issued: 2019
Photophysical properties and photodynamic therapy activities of symmetrical and asymmetrical porphyrins embedded into Pluronic polymer micelles and nonlinear optical properties of an asymmetrical phthalocyanine
- Authors: Managa, Muthumuni Elizabeth
- Date: 2019
- Subjects: Porphyrins , Phthalocyanines
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/67625 , vital:29122
- Description: This work reports on the synthesis of symmetrical and asymmetrical novel porphyrins that have been incorporated into Pluronic polymers, as well as the synthesis of asymmetrical phthalocyanine. The new compounds were characterized by elemental analysis, Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H NMR), mass spectrometry and UV–Visible spectroscopy. The porphyrins that are synthesised were not water soluble but upon incorporating into Pluronic polymer micelles, they became water soluble. The polymer was also modified and linked to folic acid, to enhance selectivity for photodynamic therapy application, where MCF7 breast cancer cells were used. The singlet oxygen quantum yields were lower for the metal free porphyrins as compared to metalled ones due to the heavy atom effect of ClGa, Zn and Cl2Si in the latter which encourages intersystem crossing to the triplet state. Singlet oxygen quantum yields for water soluble derivatives increased upon being encapsulated into the micelles for all. The Stern-Volmer constant (Ksv), binding constant (Kb) and number of binding sites (n) were investigated in order to understand the interaction between the polymer micelles and the porphyrins, and it was showed that the central metals play a role in the manner which the porphyrin interacts with the micelles. The dark toxicity and photodynamic activity of the novel porphyrins upon encapsulating to Pluronic polymer micelles is also reported. There was minimal dark toxicity for all complexes with > 90% cell survival. The photodynamic activity of water insoluble porphyrins improved when encapsulated into the micelles. Novel asymmetrical phthalocyanines were also synthesised for nonlinear optics (NLO) studies in solution and thin films.
- Full Text:
- Date Issued: 2019
- Authors: Managa, Muthumuni Elizabeth
- Date: 2019
- Subjects: Porphyrins , Phthalocyanines
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/67625 , vital:29122
- Description: This work reports on the synthesis of symmetrical and asymmetrical novel porphyrins that have been incorporated into Pluronic polymers, as well as the synthesis of asymmetrical phthalocyanine. The new compounds were characterized by elemental analysis, Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H NMR), mass spectrometry and UV–Visible spectroscopy. The porphyrins that are synthesised were not water soluble but upon incorporating into Pluronic polymer micelles, they became water soluble. The polymer was also modified and linked to folic acid, to enhance selectivity for photodynamic therapy application, where MCF7 breast cancer cells were used. The singlet oxygen quantum yields were lower for the metal free porphyrins as compared to metalled ones due to the heavy atom effect of ClGa, Zn and Cl2Si in the latter which encourages intersystem crossing to the triplet state. Singlet oxygen quantum yields for water soluble derivatives increased upon being encapsulated into the micelles for all. The Stern-Volmer constant (Ksv), binding constant (Kb) and number of binding sites (n) were investigated in order to understand the interaction between the polymer micelles and the porphyrins, and it was showed that the central metals play a role in the manner which the porphyrin interacts with the micelles. The dark toxicity and photodynamic activity of the novel porphyrins upon encapsulating to Pluronic polymer micelles is also reported. There was minimal dark toxicity for all complexes with > 90% cell survival. The photodynamic activity of water insoluble porphyrins improved when encapsulated into the micelles. Novel asymmetrical phthalocyanines were also synthesised for nonlinear optics (NLO) studies in solution and thin films.
- Full Text:
- Date Issued: 2019
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